1. Field of the Invention
The present disclosure relates generally to pipelined converter systems.
2. Description of the Related Art
Pipelined analog-to-digital signal converter systems are often used in high-speed, high-resolution conversion applications. These systems generally realize a desired number of conversion bits with a cascade (i.e., a pipeline) of lower-resolution converter stages and thus achieve high resolution at sampling speeds that are difficult to realize with other converter systems. Each stage of a pipelined system quantizes that stage's input signal to a predetermined number of digital bits and forms an analog residue signal which is presented to a succeeding stage for further signal processing.
Errors are induced into the transfer functions of the residue signals of the converter stages by various effects. When the converter stages are realized with switched capacitors and amplifiers, for example, mismatches in the capacitors and low gain in the amplifiers can both degrade the accuracy of the transfer functions. In addition, low gain in amplifiers
Although calibration methods have been proposed to reduce transfer function errors, they have generally suffered from various defects. A major one of these is the loss of dynamic range in the transfer function of the converter stage that is being calibrated.